Evolution of NITrogen BUFFERing capacity of land water interfaces along hydrosystems of different age (NITBUFFER)

不同年龄的水系统陆地水界面的氮缓冲能力的演变（NITBUFFER）

• 批准号: NE/G016917/1
• 负责人: Gilles Pinay
• 金额: $ 41.23万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG016917%2F1
• 关键词: Evolution; NITrogen; BUFFERing; capacity; land

Floodplain, riparian and in-stream zones are key regulators of energy and matter transfer in river ecosystems. More specifically, terrestrial-aquatic interfaces in riverine landscapes, e.g. riparian forest or meadow, wetlands, gravel bars, where physical sedimentation and biological activities occur; act as biogeochemical hot spots, particularly for nitrogen cycling. These interfaces also represent functional retention areas, i.e. buffer zones (Haycock et al. 1997) which control and maintain river water quality (Sabater et al. 2003). Empirical evidence has shown that the area of water-substrate interface (i.e. water-sediment or wetland-upland length of contact) is positively correlated to the efficiency of nitrogen retention and uptake in river ecosystems. Nevertheless, efforts to quantify the importance of land-water interfaces on nitrogen cycling and their buffering capacity in drainage basins have largely been unsuccessful due to; i) the discrepancy between the scales at which these interfaces have been studied in situ and the extrapolation of their capabilities at larger scales, and ii) anthropogenic activities which have led to river ecosystem fragmentation and habitat destruction in most parts of the world, disrupting the structure and function of these lotic ecosystems, such that it is difficult to accurately decipher the role of these land-water interfaces. However, riparian zones are now well recognised as a tool to allow both protection of river quality against diffuse pollution and to promote the regeneration of stream habitats. Yet, we lack a fundamental understanding of the consequences of this restoration on the nitrogen buffering capacities of these land water interfaces. Moreover the trajectory of stream restoration based on the rehabilitation of riparian zones is not fully understood, mostly because we do not know the natural mechanisms by which hydrogeomorphological and microbial processes interact and the timeframe of these interactions to achieve nitrogen buffering capacities. The overall goal of the proposed research is to use watersheds of different ages and complexity that have developed during the last 250 years following deglaciation in Glacier Bay, southeast Alaska as a natural in-situ laboratory under maritime climate to analyse the co-evolution of hydrogeomorphic development and microbial processes controlling nitrogen buffering capacity in hydrosystems' land water interfaces. This research will provide the first insights into the natural timeframe of land water interface formation and development, and their consequences on nitrogen regulation in stream catchments. The choice of pristine hydrosystems under Maritime climate in Glacier Bay is appropriate due to: i) the existence of a well documented chronosequence, both in terms of vegetation and stream fauna successions; ii) space-for-time strategies can be used to quantify rates of change of land water structure and functions; iii) geochemical tracers are not influenced by past and present human legacy in this pristine context, and iv) the selection of drainage basins of similar size (ca 10 km2) permits to determine the importance of landscape structure and arrangement on N fluxes to be determined. This natural in-situ laboratory allows the formulation and testing of hypotheses related to the formation of the land water interface and the development of their nitrogen buffering capacity. In situ rate measurements of microbial processes regulating nitrogen cycles in land water interfaces, and organic matter character and concentration, together with geochemical indicators, will provide valuable data on the rate of evolution of nitrogen land water buffer zones. These data are essential for understanding the consequences of deglaciation on greenhouse gas emissions (N2O, CO2, CH4) and the mechanisms by which nitrogen buffering capacity develop over time.

洪泛区、河岸带和河流带是河流生态系统能量和物质转移的关键调节器。更具体地说，河流景观中的陆地-水生界面，例如发生物理沉积和生物活动的河岸森林或草地、湿地、砾石坝；是生物地球化学热点，特别是对氮循环而言。这些界面也代表功能保留区，即缓冲区(Haycock等人。1997)，控制和维护河流水质(Sabater等人。2003年)。经验证据表明，水-基质界面面积(即水-沉积物或湿地-旱地接触长度)与河流生态系统中氮的截留和吸收效率呈正相关。然而，量化陆地-水界面对氮循环的重要性及其在流域中的缓冲能力的努力在很大程度上是不成功的，原因是：i)现场研究这些界面的规模与在更大尺度上推断其能力之间的差异，以及ii)导致世界大部分地区河流生态系统碎片化和栖息地破坏的人为活动，扰乱了这些热带生态系统的结构和功能，从而难以准确地破译这些陆地-水界面的作用。然而，河岸地带现在被公认为既可以保护河流质量不受扩散污染，又可以促进溪流栖息地的再生。然而，我们对这种恢复对这些陆水界面的氮缓冲能力的影响缺乏基本的了解。此外，以河岸带恢复为基础的河流恢复的轨迹尚未完全了解，主要是因为我们不知道水文地貌和微生物过程相互作用的自然机制以及这些相互作用达到氮缓冲能力的时间框架。拟议研究的总体目标是利用阿拉斯加东南部冰川湾冰川消融后过去250年间形成的不同年龄和复杂程度的流域作为海洋性气候下的自然原位实验室，分析水文地貌发育和控制水文系统陆水界面氮缓冲能力的微生物过程的共同演变。这项研究将首次深入了解陆水界面形成和发展的自然时间框架，以及它们对河流流域氮素调节的影响。选择冰川湾海洋气候下的原始水文系统是适当的，因为：i)在植被和河流动物演替方面都存在一个有充分记录的时间序列；ii)可以利用时空战略来量化陆地水结构和功能的变化率；iii)在这种原始环境中，地球化学示踪剂不受过去和现在人类遗产的影响；以及iv)类似大小的流域(约10平方公里)的选择允许确定景观结构和安排对N通量的重要性。这个天然的就地实验室允许制定和测试与陆地水界面的形成和发展其氮缓冲能力有关的假说。对调节陆水界面氮循环的微生物过程、有机质特征和浓度以及地球化学指标的现场速率测量，将为陆地水中氮素缓冲区的演化速度提供宝贵的数据。这些数据对于理解冰川消融对温室气体(N2O、CO2、CH4)排放的影响以及氮缓冲能力随时间发展的机制至关重要。

项目成果

Vegetation succession in deglaciated landscapes: implications for sediment and landscape stability

• DOI: 10.1002/esp.3691
• 发表时间: 2015-06
• 期刊: Earth Surface Processes and Landforms
• 影响因子: 3.3
• 作者: M. Klaar;C. Kidd;Edward T. Malone;R. Bartlett;G. Pinay;F. Chapin;A. Milner

The effects of climatic fluctuations and extreme events on running water ecosystems.

• DOI: 10.1098/rstb.2015.0274
• 发表时间: 2016-05-19
• 期刊: Philosophical transactions of the Royal Society of London. Series B, Biological sciences
• 作者: Woodward G;Bonada N;Brown LE;Death RG;Durance I;Gray C;Hladyz S;Ledger ME;Milner AM;Ormerod SJ;Thompson RM;Pawar S
• 通讯作者: Pawar S